Industrial oil comprising a bio-derived ester

ABSTRACT

An industrial oil composition comprises a major amount of an ester base oil comprised of at least one diester or triester species having a vicinal diester substituent and at least one additive. The use of such esters can provide biodegradable industrial oils having improved viscosity index, additive solvency, or both.

TECHNICAL FIELD

The application generally relates to industrial oil compositionscomprised of an ester having a vicinal diester substituent. The use ofsuch esters can provide biodegradable industrial oils having highviscosity index.

BACKGROUND

Naphthenic base oils, or pale oils, are produced from feedstocks rich innaphthenes and low in wax content. Because of their low wax content,naphthenic base oils have lower pour points and better additive solvencycharacteristics than paraffinic base oils which make naphthenic oilsparticularly useful in formulating low temperature lubricating oils suchas industrial oils. Naphthenic base oils have a low viscosity index(e.g., 40 to 80) which makes them less suitable for use in applicationswhere a wide temperature occurs, unless expensive viscosity indeximprovers are added. In addition, naphthenic base oils have poorbiodegradability and have high aromatics content. Naphthenic base oilsare defined as Group V base oils according to the American PetroleumInstitute (API).

Ester-based lubricants, in general, have excellent lubricationproperties due to the polarity of the ester molecules of which they arecomprised and are relatively stable to thermal and oxidative processes.They have characteristics similar to naphthenic base oils such as lowpour points and good additive solvency. In addition, ester-basedlubricants have much higher viscosity indexes than naphthenic base oilsand have excellent biodegradability.

Currently, a number of commercial esters are available as lubricants.These include mono-esters, diesters, phthalate esters, trimellitateesters and polyol esters. These commercial esters are either generallypoor lubricants (for one or more of a variety of reasons) or relativelyexpensive.

Recently, novel bio-derived esters have been described, for example, inU.S. Pat. Nos. 7,544,645; 7,867,959; and 7,871,967. The bio-derivedester syntheses described in these patents can render the economics ofester lubricant formations more favorable.

In view of the foregoing, providing a more economical industrial oilcomprising an ester with improved lubricating properties, particularlywherein the ester is at least partially derived from a renewableresource, would be highly desirable.

SUMMARY

In one aspect, we provide an industrial oil comprising a major amount ofan ester base oil comprised of at least one diester or triester specieshaving a vicinal diester substituent and at least one additive. Theindustrial oil is selected from the group consisting of a hydraulic oil,a rock drill oil, a saw guide oil, and a way oil.

In another aspect, we provide a method for improving an industrial oilcomprising selecting an ester base oil comprised of at least one diesteror triester species having a vicinal diester substituent; and replacingat least a portion of an original base oil in an original industrial oilwith the ester base oil to produce an improved industrial oil, whereinviscosity index, additive solvency or both of the improved industrialoil is higher compared to an original viscosity index, an originaladditive solvency or both of the original industrial oil without theester base oil. In some embodiments, the original base oil is anaphthenic base oil. In some embodiments, the viscosity index of theimproved industrial oil is at least 50 (e.g., 60, 70, 80, 90 or 100)greater than the original viscosity index of the original industrialoil.

DETAILED DESCRIPTION

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

The prefix “bio” refers to an association with a renewable resource ofbiological origin, such resources generally being exclusive of fossilfuels. Such an association is typically that of derivation, i.e., abio-ester derived from a biomass precursor material.

“Vicinal” refers to the attachment of two functional groups (e.g., estergroups) to adjacent carbons in a hydrocarbon-based molecule.

“C_(n)” describes a hydrocarbon molecule or fragment (e.g., an alkylgroup) wherein “n” denotes the number of carbon atoms in the molecule orfragment.

“Carbon number” is used herein in a manner analogous to that of “C_(n).”The carbon number refers to the total of carbon atoms in a molecule (orfragment) regardless of whether or not it is purely hydrocarbon innature. Lauric acid, for example, has a carbon number of 12.

“Kinematic viscosity” is a measurement in mm²/s of the resistance toflow of a fluid under gravity, determined by ASTM D445-11a (“StandardTest Method for Kinematic Viscosity of Transparent and Opaque Liquids(and Calculation of Dynamic Viscosity)”).

“Viscosity index” (VI) is an empirical, unit-less number indicating theeffect of temperature change on the kinematic viscosity of the oil. Thehigher the VI of an oil, the lower its tendency to change viscosity withtemperature. Viscosity index is measured according to ASTM D2270-10(“Standard Practice for Calculating Viscosity Index from KinematicViscosity at 40 and 100° C.”).

“Pour point” represents the lowest temperature at which a fluid willpour or flow. See, e.g., ASTM D97-11 (“Standard Test Method for PourPoint of Petroleum Products”), ASTM D5950-02 (Reapproved 2007)(“Standard Test Method for Pour Point of Petroleum Products (AutomaticTilt Method)”), and ASTM D6892-03 (Reapproved 2008) (“Standard TestMethod for Pour Point of Petroleum Products (Robotic Tilt Method)”).

“Cloud point” represents the temperature at which a fluid begins tophase separate due to crystal formation. See, e.g., ASTM D2500-11(“Standard Test Method for Cloud Point of Petroleum Products”), ASTMD5551-95 (Reapproved 2006) (“Standard Test Method for Determination ofthe Cloud Point of Oil”), ASTM D5771-10 (“Standard Test Method for CloudPoint of Petroleum Products (Optical Detection Stepped Cooling Method)”)and ASTM D5773-10 (“Standard Test Method for Cloud Point of PetroleumProducts (Constant Cooling Rate Method)”).

“Oxidation stability” generally refers to a composition's resistance tooxidation. Oxidator BN is a convenient way to measure the oxidationstability of base oils. The Oxidator BN test is described in U.S. Pat.No. 3,852,207. The Oxidator BN test measures the resistance of an oil tooxidation by means of a Dornte-type oxygen absorption apparatus. See R.W. Dornte, Ind. Eng. Chem. 1936, 28, 26-30. Normally, the conditions are1 atmosphere of pure oxygen at 340° F. (171° C.). The results arereported in hours to absorb 1000 mL of O₂ by 100 g of oil.

Ester Base Oil

The industrial oil comprises a major amount of an ester base oilcomprised of at least one diester or triester species having a vicinaldiester substituent. As used herein, the term “major amount” refers to aconcentration of the ester base oil within the industrial oil of atleast 50 wt. %. The amount of the ester base oil in the industrial oilranges from 50 to 99 wt. %, e.g., 60 to 98 wt. %, 70 to 97 wt. %, or 80to 96 wt. %, based on the total weight of the industrial oil.

Diester Species

In some embodiments, the ester base oil comprises a diester specieshaving the following chemical structure (1):

wherein R¹, R², R³, and R⁴ are independently selected from hydrocarbongroups having from 2 to 17 carbon atoms.

Regarding the above-mentioned diester species, the selection of R¹, R²,R³, and R⁴ can follow any or all of several criteria. For example, insome embodiments, R¹, R², R³, and R⁴ are selected such that thekinematic viscosity at 100° C. of the industrial oil is typically 3mm²/s or greater. In some or other embodiments, R¹, R², R³, and R⁴ areselected such that the pour point of the resulting industrial oil is−10° C. or lower, −25° C. or lower; or even −40° C. or lower. In someembodiments, R¹ and R² are selected to have a combined carbon number(i.e., total number of carbon atoms) of from 6 to 14. In these or otherembodiments, R³ and R⁴ are selected to have a combined carbon number offrom 10 to 34. Depending on the embodiment, such resulting diesterspecies can have a molecular mass between 340 atomic mass units (a.m.u.)and 780 a.m.u.

In some embodiments, the ester base oil is substantially homogeneous interms of its diester species. In some or other embodiments, the esterbase oil comprises a mixture of diester species.

In some embodiments, the ester base oil comprises at least one diesterspecies derived from a C₈ to C₁₆ olefin and a C₂ to C₁₈ carboxylic acid.The diester species can be made by reacting the parent diol (on theintermediate) with different acids to make mixed diesters, but suchdiester species can also be made by reacting the diol with the sameacid.

In some embodiments, the diester species is selected from the groupconsisting of decanoic acid 2-decanoyloxy-1-hexyl-octyl ester and itsisomers, tetradecanoic acid-1-hexyl-2-tetradecanoyloxy-octyl esters andits isomers, dodecanoic acid 2-dodecanoyloxy-1-hexyl-octyl ester and itsisomers, hexanoic acid 2-hexanoyloxy-1-hexyl-octyl ester and itsisomers, octanoic acid 2-octanoyloxy-1-hexyl-octyl ester and itsisomers, hexanoic acid 2-hexanoyloxy-1-pentyl-heptyl ester and itsisomers, octanoic acid 2-octanoyloxy-1-pentyl-heptyl ester and itsisomers, decanoic acid 2-decanoyloxy-1-pentyl-heptyl ester and itsisomers, decanoic acid-2-decanoyloxy-1-pentyl-heptyl ester and itsisomers, dodecanoic acid-2-dodecanoyloxy-1-pentyl-heptyl ester and itsisomers, tetradecanoic acid 1-pentyl-2-tetradecanoyloxy-heptyl ester andits isomers, tetradecanoic acid 1-butyl-2-tetradecanoyloxy-hexyl esterand its isomers, dodecanoic acid-1-butyl-2-dodecanoyloxy-hexyl ester andits isomers, decanoic acid 1-butyl-2-decanoyloxy-hexyl ester and itsisomers, octanoic acid 1-butyl-2-octanoyloxy-hexyl ester and itsisomers, hexanoic acid 1-butyl-2-hexanoyloxy-hexyl ester and itsisomers, tetradecanoic acid 1-propyl-2-tetradecanoyloxy-pentyl ester andits isomers, dodecanoic acid 2-dodecanoyloxy-1-propyl-pentyl ester andits isomers, decanoic acid 2-decanoyloxy-1-propyl-pentyl ester and itsisomers, octanoic acid 1-2-octanoyloxy-1-propyl-pentyl ester and itsisomers, hexanoic acid 2-hexanoyloxy-1-propyl-pentyl ester and itsisomers, and mixtures thereof.

Processes for Making the Diester

Methods which can be employed in making the diester species are furtherdescribed in U.S. Pat. Nos. 7,867,959 and 7,871,967 and U.S. PatentApplication Publication Nos. 2010/0120642; 2010/0261627; and2011/0077184.

More specifically, in some embodiments, the process for making theabove-mentioned diester species, comprises the following steps: (a)epoxidizing an olefin (or quantity of olefins) having from 8 to 16carbon atoms to form an epoxide; (b) hydrolyzing the epoxide to form adiol; and (c) esterifying (i.e., subjecting to esterification) the diolwith an esterifying agent having from 2 to 18 carbon atoms to form thediester species, wherein the esterifying agent is selected from thegroup consisting of carboxylic acids, acyl halides, acid anhydrides, andcombinations thereof. The diester species has a kinematic viscosity at100° C. of 3 mm²/s or more.

In some embodiments, the diester species can be prepared by epoxidizingan olefin having from 8 to 16 carbon atoms to form an epoxide. Theepoxide is reacted directly with an esterifying agent having from 2 to18 carbon atoms to form the diester species, wherein the esterifyingagent is selected from the group consisting of carboxylic acids, acylhalides, acid anhydrides, and combinations thereof. The diester specieshas a viscosity and a pour point suitable for use as an industrial oil.

In some embodiments, where a quantity of the diester species is formed,the quantity of the diester species can be substantially homogeneous, orit can be a mixture of two or more different diester species.

In some embodiments, the olefin is a reaction product of aFischer-Tropsch process. In some embodiments, the olefin is a mixture ofisomeric olefins and/or a mixture of olefins having a different numberof carbon atoms. In some embodiments, the carboxylic acid can be derivedfrom alcohols generated by a Fischer-Tropsch process and/or it can be abio-derived fatty acid.

In some embodiments, the olefin is an alpha olefin (i.e., an olefinhaving a double bond at a chain terminus). It is sometimes necessary toisomerize the alpha olefin so as to internalize the double bond. Suchisomerization can be carried out using a catalyst such as, but notlimited to, crystalline aluminosilicate and like materials andaluminophosphates. See, e.g., U.S. Pat. Nos. 2,537,283; 3,211,801;3,270,085; 3,327,014; 3,304,343; 3,448,164; 3,723,564; 4,593,146; and6,281,404.

For example, Fischer-Tropsch alpha olefins can be isomerized to thecorresponding internal olefins followed by epoxidation. The epoxides canthen be transformed to the corresponding diols via epoxide ring openingfollowed by di-acylation (i.e., di-esterification) with the appropriatecarboxylic acids or their acylating derivatives. It is sometimesnecessary to convert alpha olefins to internal olefins because diestersof alpha olefins, especially short chain alpha olefins, can tend to besolids or waxes. “Internalizing” alpha olefins followed bytransformation to the diester functionalities introduces branching alongthe chain which reduces the pour point of the intended products. It istypically preferable to have a few longer branches than many shortbranches, since increased branching tends to lower the viscosity index.

Regarding the step of epoxidizing (i.e., the epoxidation step), in someembodiments, the above-described olefin (in one embodiment, an internalolefin) can be reacted with a peroxide (e.g., H₂O₂) or a peroxy acid(e.g., peroxyacetic acid) to generate an epoxide. See, e.g., D. Swern,in Organic Peroxides Vol. II, Wiley-Interscience, New York, 1971,355-533; and B. Plesnicar, in Oxidation in Organic Chemistry, Part C, W.Trahanovsky (ed.), Academic Press, New York 1978, 221-253. Olefins canbe efficiently transformed to the corresponding vicinal diols by highlyselective reagents such as osmium tetroxide or potassium permanganate(see, e.g., A. H. Haines, Methods for the Oxidation of OrganicCompounds: Alkanes, Alkenes, Alkynes, and Arenes, Academic Press,London, 1985, 75-91).

Regarding the step of hydrolyzing the epoxide to form the correspondingdiol, this step can be acid-catalyzed or base-catalyzed. Exemplary acidcatalysts include, but are not limited to, mineral-based Brønsted acids(e.g., HCl, H₂SO₄, H₃PO₄, perhalogenates, etc.), Lewis acids (e.g.,TiCl₄ and AlCl₃), solid acids such as acidic aluminas and silicas ortheir mixtures, and the like. See, e.g., R. E. Parker et al., Chem. Rev.1959, 59, 737-799. Base-catalyzed hydrolysis typically involves the useof bases such as aqueous solutions of sodium or potassium hydroxide.

Regarding the step of esterifying (esterification) the diol, an acid istypically used to catalyze the reaction between the hydroxyl groups ofthe diol and the carboxylic acid(s). Suitable acids include, but are notlimited to, sulfuric acid (see, e.g., J. Munch-Petersen, Org. Syntheses,Coll. Vol. 5, 1973, p. 762), a sulfonic acid (see, e.g., C. F. H. Allenet al., Org. Syntheses, Coll. Vol. 3, 1955, p. 203), hydrochloric acid(see, e.g., E. L. Eliel et al., Org. Syntheses, Coll. Vol. 4, 1963 p.169), and phosphoric acid (among others). In some embodiments, thecarboxylic acid used in this step is first converted to an acyl chloride(via, e.g., thionyl chloride or PCl₃). Alternatively, an acyl chloridecould be employed directly. When an acyl chloride or an acid anhydrideis used as an esterifying agent, a base such as pyridine,4-dimethylaminopyridine (DMAP) or triethylamine (TEA) can be added toaccelerate the rate of the reaction. When pyridine or DMAP is used, itis believed that these amines also act as a catalyst by forming a morereactive acylating intermediate (see, e.g., A. R. Fersht et al., J. Am.Chem. Soc. 1970, 92, 5432-5442; and G. Hofle et al., Angew. Chem. Int.Ed. Engl. 1978, 17, 569-583).

Regarding the step of directly esterifying an epoxide, in someembodiments, this step is carried out in the presence of a catalyst.Such catalysts can include, but are not limited to, H₃PO₄, H₂SO₄,sulfonic acids, Lewis acids, silica- and alumina-based solid acids,AMBERLYST™ polymer-based catalysts, tungsten oxide, and mixturesthereof.

Regardless of the source of the olefin, in some embodiments, thecarboxylic acid used in the above described method is derived frombiomass. In some such embodiments, this involves the extraction of someoil (e.g., triglyceride) component from the biomass and hydrolysis ofthe triglycerides of which the oil component is comprised so as to formfree carboxylic acids.

Triester Species

In some embodiments, the ester base oil comprises a triester specieshaving the following chemical structure (2):

wherein R⁵, R⁶, R⁷, and R⁸ are independently selected from hydrocarbongroups having from 2 to 20 carbon atoms, and wherein “n” is an integerfrom 2 to 20.

Regarding the above-mentioned triester species (2), selection of R⁵, R⁶,R⁷, and R⁸, and “n” can follow any or all of several criteria. Forexample, in some embodiments, R⁵, R⁶, R⁷, and R⁸ and “n” are selectedsuch that the kinematic viscosity at 100° C. of the industrial oil istypically 3 mm²/s or greater. In some or other embodiments, R⁵, R⁶, R⁷,and R⁸ and “n” are selected such that the pour point of the resultingindustrial oil is −10° C. or lower, e.g., −25° C. or even −40° C. orlower. In some embodiments, R⁵ is selected to have a total carbon numberof from 6 to 12. In these or other embodiments, R⁶ is selected to have acarbon number of from 2 to 20. In these or other embodiments, R⁷ and R⁸are selected to have a combined carbon number of from 4 to 36. In theseor other embodiments, “n” is selected to be an integer from 5 to 10.Depending on the embodiment, such resulting triester species can have amolecular mass between 400 a.m.u. and 1100 a.m.u., or between 450 a.m.u.and 1000 a.m.u.

In some of the above-described embodiments, the triester species (2)used to prepare the industrial oil comprises one or more triesterspecies of the type 9,10-bis-alkanoyloxy-octadecanoic acid alkyl esterand isomers and mixtures thereof, where the alkyl is selected from thegroup consisting of ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl,nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, and octadecyl; and where the alkanoyloxy is selected from thegroup consisting of ethanoyloxy, propanoyloxy, butanoyloxy,pentanoyloxy, hexanoyloxy, heptanoyloxy, octanoyloxy, nonoyloxy,decanoyloxy, undecanoyloxy, dodecanoyloxy, tridecanoyloxy,tetradecanoyloxy, pentadecanoyloxy, hexadecanoyloxy, andoctadecanoyloxy. Exemplary such triesters include9,10-bis-hexanoyloxy-octadecanoic acid hexyl ester and9,10-bis-decanoyloxy-octadecanoic acid decyl ester.

In some embodiments, the ester base oil comprises a triester specieshaving the following chemical structure (3):

wherein R⁹, R¹⁰, R¹¹, and R¹² are independently selected fromhydrocarbon groups having from 2 to 20 carbon atoms, and wherein “n” isan integer from 2 to 20.

For the above-described triester species (3), R⁹ is typically selectedto have a total carbon number of from 6 to 12, R¹¹ and R¹² are typicallyselected to have a combined carbon number of from 2 to 40, R¹⁰ istypically selected to have a carbon number of from 2 to 20, and “n” istypically an integer in the range of from 5 to 10. Depending on theembodiment, such resulting triester species (3) can have a molecularmass between 400 a.m.u. and 1100 a.m.u, or between 450 a.m.u. and 1000a.m.u.

In some embodiments, the triester species (3) is selected from the groupconsisting of octadecane-1,9,10-triyl trihexanoate;octadecane-1,9,10-triyl triheptanoate; octadecane-1,9,10-triyltrioctanoate; octadecane-1,9,10-triyl trinonoate;octadecane-1,9,10-triyl tris(decanoate); octadecane-1,9,10-triyltidodecanoate; octadecane-1,9,10-triyl triundecanoate;octadecane-1,9,10-triyltridodecanoate; octadecane1,9,10-triyltridecanoate; and octadecane-1,9,10-triyl tritetradecanoate;and mixtures thereof.

In some embodiments, the ester base oil is substantially homogeneous interms of its triester species. In some other embodiments, the ester baseoil comprises a mixture of triester species.

Processes for Making the Triester

Processes which can be employed in making the triesters are furtherdescribed in U.S. Pat. No. 7,544,645 and U.S. Patent ApplicationPublication No. 2010/0311625.

More specifically, in some embodiments, the process for making thetriester species (2) comprises the following steps: (a) esterifying(i.e., subjecting to esterification) a mono-unsaturated fatty acid (orquantity of mono-unsaturated fatty acids) having from 10 to 22 carbonatoms with an alcohol to form an unsaturated ester (or a quantitythereof); (b) epoxidizing the unsaturated ester to form an epoxy-esterspecies comprising an epoxide ring; (c) hydrolyzing the epoxide ring ofthe epoxy-ester species to form a dihydroxy-ester species; and (d)esterifying the dihydroxy-ester species with an esterifying agent havingfrom 2 to 18 carbon atoms to form the triester species, wherein theesterifying agent is selected from the group consisting of carboxylicacids, acyl halides, acid anhydrides, and combinations thereof.

In some embodiments, the process for making the triester species (3) cancomprise reducing a mono-unsaturated fatty acid to form an unsaturatedalcohol. The unsaturated alcohol is then epoxidized to form anepoxy-alcohol species comprising an epoxide ring. The epoxide ring ofthe epoxy-alcohol species is hydrolyzed to form a triol; and then thetriol is esterified with an esterifying agent having from 2 to 18 carbonatoms to form the triester species, wherein the esterifying agent isselected from the group consisting of carboxylic acids, acyl halides,acid anhydrides, and combinations thereof.

In other embodiments, the process for making the triester species (3)can comprise (a) reducing a mono-unsaturated fatty acid to form anunsaturated alcohol; (b) epoxidizing the unsaturated alcohol to form anepoxy-alcohol species comprising an epoxide ring; and (c) esterifyingthe epoxy-alcohol species with an esterifying agent having from 2 to 18carbon atoms to form the triester species, wherein the esterifying agentis selected from the group consisting of carboxylic acids, acyl halides,acid anhydrides, and combinations thereof.

In some embodiments, where a quantity of the triester species is formed,the quantity of triester species can be substantially homogeneous, or itcan be a mixture of two or more different such triester species.Additionally or alternatively, in some embodiments, such processesfurther comprise a step of blending the triester species with one ormore diester species.

In some embodiments, the step of esterifying (i.e., esterification) themono-unsaturated fatty acid can proceed via an acid-catalyzed reactionwith an alcohol using, e.g., H₂SO₄ as a catalyst. In some or otherembodiments, the esterifying can proceed through a conversion of thefatty acid(s) to an acyl halide (e.g., chloride, bromide, or iodide) oracid anhydride, followed by reaction with an alcohol. In someembodiments, the mono-unsaturated fatty acid is a bio-derived fattyacid. In some such embodiments, this involves the extraction of some oil(e.g., triglyceride) component from the biomass and hydrolysis of thetriglycerides of which the oil component is comprised so as to form freecarboxylic acids. In some embodiments, the alcohol(s) is derived from aFischer-Tropsch process.

Regarding the step of reducing a mono-unsaturated fatty acid to thecorresponding unsaturated alcohol, lithium aluminum hydride can be usedas the reducing agent in some embodiments. In other embodiments,particularly for industrial-scale processes, catalytic hydrogenation canbe employed using, for example, copper- or zinc-based catalysts. See,e.g., U.S. Pat. No. 4,880,937; C. Scrimgeour, “Chemistry of FattyAcids,” in Bailey's Industrial Oil and Fat Products, Sixth Edition, Vol.1, 1-43, F. Shahidi (Ed.), J. Wiley & Sons, New York, 2005.

Regarding the step of epoxidizing (i.e., the epoxidation step), thisstep is generally consistent with that as previously described herein.

Regarding the step of hydrolyzing the epoxide ring via acid- orbase-catalysis, this step is generally consistent with that aspreviously described herein.

Regarding the step of directly esterifying an epoxide, this step isgenerally consistent with that as previously described herein.

Additives

The industrial oil comprises at least one additive. Additives caninclude, for example, pour point depressants, anti-wear agents, EPagents, detergents, dispersants, antioxidants, viscosity indeximprovers, friction modifiers, demulsifiers, foam inhibitors, corrosioninhibitors, rust inhibitors, seal swell agents, emulsifiers, wettingagents, lubricity improvers, metal deactivators, gelling agents,tackiness agents, bactericides, fungicides, thickeners, fluid-lossadditives, colorants, and the like. In some embodiments, the industrialoil is substantially free of any viscosity index improver. As usedherein, the term “substantially free” shall be understood to meanrelatively little to no amount of any viscosity index improver, e.g., anamount less than about 0.5 wt. %, less than 0.25 wt. %, or less than 0.1wt. %, based on the total weight of the industrial oil composition.

In some embodiments, the industrial oil has a viscosity index of atleast 140, e.g., from 140 to 300; in some embodiments, at least 150. Insome embodiments, the industrial oil has a kinematic viscosity at 100°C. of from 3 mm²/s to 25 mm²/s, or from 4 mm²/s to 20 mm²/s.

EXAMPLES

The following examples are given to illustrate the present invention. Itshould be understood, however, that the invention is not to be limitedto the specific conditions or details described in these examples.

As an exemplary synthetic procedure, the synthesis of a diester specieshaving a vicinal diester substituent is described in Examples 1-2.

Example 1 Synthesis of C₁₄ Diol Isomers

In a 3-neck 3 L reaction flask equipped with an overhead stirrer andplaced in an ice bath, 260 g of 30% hydrogen peroxide (2.3 mol) wasadded to 650 g of 88 wt. % formic acid (12.4 mol). To this mixture, 392g (2 mol) of a mixture of tetradecene isomers (i.e., a mixture of thefollowing: 1-tetradecene, 2-tetradecene, 3-tetradecene, 4-tetradecene,5-tetradecene, 6-tetradecene and 7-tetradecene) was added slowly over a45-minute period via an addition funnel while ensuring that the reactiontemperature stayed below 45° C. Once the addition of the olefin wascomplete, the reaction was allowed to stir for 2 hours while cooling inan ice bath to prevent a rise in the temperature above 40° C. to 45° C.The ice bath was then removed and the reaction was stirred at roomtemperature overnight. The reaction mixture was concentrated with arotary evaporator in a hot water bath at approximately 30 mm Hg (Torr)to remove most of the water and formic acid. Then, 400 mL of an ice-cold1 M solution of sodium hydroxide was added very slowly (i.e., in smallportions) to the remaining residue of the reaction. Once all the sodiumhydroxide solution was added, the mixture was allowed to stir for anadditional 2 hours at about 80° C. The mixture was then diluted with 500mL of ethyl acetate and transferred to a separatory funnel. The organiclayer was separated and the aqueous layer was extracted 3 times withethyl acetate (300 mL each). The ethyl acetate extracts were allcombined and dried over anhydrous MgSO₄. Filtration, followed byconcentration on a rotary evaporator at reduced pressure in a hot waterbath yielded a tetradecene-diol mixture (diol isomers prepared from thetetradecene isomers) as a waxy substance in 96% yield (443 g). Thetetradecene-diols were characterized by infrared (IR), nuclear magneticresonance (NMR) spectroscopy and gas chromatography/mass spectrometry(GC/MS).

Example 2 Synthesis of Diesters from C₁₄ Diol Isomers and Lauric Acid

In a 3-neck 1 L reaction flask equipped with an overhead stirrer, refluxcondenser, and a dropping funnel, 440 g (0.95 mol) of thetetradecene-diol mixture (prepared as described in Example 1), 1148 g(5.7 mol) of lauric acid, and 17.5 g of 85 wt. % H₃PO₄ (0.15 mol) weremixed. The resulting mixture was heated to 150° C. and stirred forseveral hours while monitoring the progress of the reaction by NMR andGC/MS. After stirring for 6 hours, the reaction was complete and themixture cooled down to room temperature. The reaction mixture was washedwith 1000 mL of water and the organic layer was separated using aseparatory funnel. The organic layer was further rinsed with brinesolution (1000 mL of saturated sodium chloride solution). The resultingmixture was then distilled at 220° C. and 100 mm Hg (Torr) to removeexcess lauric acid. The diester product (the remaining residue in thedistillation flask) was recovered as faint yellow oil in 84% yield (1000g). The mixture of diesters (diester product) was hydrogenated to removeany residual olefins that could have formed by elimination during theesterification reaction. The colorless oil so obtained was analyzed byIR, NMR and GC/MS.

As an exemplary synthetic procedure, the synthesis of a triester specieshaving a vicinal diester substituent is described in Examples 3-8. Thisprocedure is representative for making triesters from mono-unsaturatedcarboxylic acids and alcohols, in accordance with some embodiments ofthe present invention.

Example 3 Synthesis of Oleoyl Chloride

A three-neck 2-L round bottom reaction flask was fitted with amechanical stirrer, reflux condenser and a water-filled trap to catchthe evolving SO₂ and HCl gases. The flask was charged with 500 mL ofdichloromethane and 168 g (0.14 mol) of thionyl chloride. The reactionwas cooled to 0° C. and 200 g (0.71 mol) of oleic acid was addeddrop-wise to the reaction vessel via an addition funnel. Once all of theoleic acid was added, the reaction mixture was refluxed until theevolution of gases ceased. The reaction mixture was cooled andconcentrated on a rotary evaporator under reduced pressure to remove thesolvent (dichloromethane) and excess thionyl chloride. The reactionafforded the oleoyl chloride as viscous oil in about 98% yield (210 g).The product was confirmed by NMR, IR and GC/MS.

Example 4 Synthesis of Hexyl Oleate

In a 3-neck 2-L reaction flask equipped with a mechanical stirrer,dropping funnel and a reflux condenser, 100 g (0.33 mol) of oleoylchloride (synthesized according to the procedure described in Example 3)was added drop-wise to a solution of 51 g (0.5 mol) of hexanol and 42 g(0.41 mol) of triethylamine at 0° C. in 800 mL of anhydrous hexanes.Once the addition was complete, the reaction mixture was heated toreflux overnight. The reaction mixture was cooled down and neutralizedwith water. The two-layer solution was transferred to a reparatoryfunnel, and the organic layer was separated and washed a few times withwater. The aqueous layer was extracted with 500 mL of ether, and theether extract was added to the organic layer and dried over MgSO₄.Filtration and concentration at reduced pressure gave the hexyl oleatemixed with excess hexanol. The products were purified by columnchromatography by eluting first with hexanes and then with 3% ethylacetate in hexane. The product was isolated as pale yellow oil. Theproduct identity was confirmed by NMR, IR and GC/MS. The reactionafforded a 93% yield (112 g) of hexyl oleate. Hexyl oleate has thefollowing structure:

Example 5 Epoxidation of Hexyl Oleate

A 1-L round bottom 3-neck reaction flask was equipped with a mechanicalstirrer, powder funnel, and a reflux condenser. The flask was chargedwith 500 mL of dichloromethane and 110 g (0.3 mol) of hexyl oleate asprepared in Example 4. The solution was cooled to 0° C., and 1101 g of77% m-chloroperoxybenzoic acid (0.45 mol mCPBA) was added in smallportions over a period of about 30 minutes. Once all of the mCPBA wasadded, the reaction was allowed to stir for 48 hours at roomtemperature. The resulting milky reaction solution was filtered, and thefiltrate was washed twice with the slow addition of a 10% aqueoussolution of sodium bicarbonate. The organic layer was washed severaltimes with water, dried over anhydrous MgSO₄, and filtered. The filtratewas evaporated to give a waxy looking substance. The product wasconfirmed by NMR, IR and GC/MS. The reaction yielded 93 g (81%) ofproduct. The product has the following structure:

Example 6 Synthesis of 9,10-Dihydroxy-octadecanoic Acid Hexyl Ester

In a 1-L reaction flask equipped with an overhead stirrer, 90 g (0.23mol) of the epoxy-ester prepared in Example 5 was suspended in 300 mL ofa 3 wt. % aqueous solution of perchloric acid and 300 mL of hexane. Thesuspension was vigorously stirred for 3 hours. The two-layer solutionwas separated and the aqueous layer was extracted with 300 mL of ethylacetate. The organic phases were combined and dried over MgSO₄.Filtration and concentration at reduced pressure on a rotary evaporatorproduced a viscous oil. Upon standing at room temperature, the oilseparated into an oily phase and a white precipitate. The solids wereseparated from the oil by filtration. IR and GC/MS analysis showed thesolid to be the dihydroxy-ester species. The reaction affordedapproximately 52% (47 g) of the 9,10-dihydroxy-octadecanoic acid hexylester. 9,10-Dihydroxy-octadecanoic acid hexyl ester has the followingstructure:

Example 7 Synthesis of 9,10-Bis-hexanoyloxy-octadecanoic Acid HexylEster

In a 1-L 3-neck reaction flask equipped with an overhead stirrer, refluxcondenser, and a heating mantle, 45 g (0.11 mol) of thedihydroxy-ester(9,10-dihydroxy-octadecanoic acid hexyl ester, preparedaccording to the procedure of Example 6) and 33 g of triethylamine (0.33mol) were mixed in 250 mL of anhydrous hexanes. To this mixture, 44 g(0.33 mol) of hexanoyl chloride was added dropwise via an additionfunnel over a 30-minute period. Once the addition was completed, thereaction was refluxed for 48 h. The resulting milky solution wasneutralized with water. The resulting two-phase solution was separatedby means of a reparatory funnel. The organic layer was washedextensively with water and the aqueous layer was extracted with 300 mLof ether. The organic layers were combined and dried over anhydrousMgSO₄, filtered, and concentrated at reduced pressure. GC/MS analysis ofthe product indicated the presence of hexanoic acid. The product wasthen washed with an ice-cold sodium carbonate solution to remove theresidual hexanoic acid. The solution was extracted with ethyl acetatewhich was dried over Na₂SO₄, filtered, and concentrated to give thefinal triester as a colorless oil in 83% yield (65 g). The product wasconfirmed by NMR, IR and GC/MS. 9,10-Bis-hexanoyloxy-octadecanoic acidhexyl ester has the following structure:

Example 8 Synthesis of 9,10-Bis-decanoyloxy-octadecanoic Acid DecylEster

Decyl oleate was synthesized using the synthetic protocols described inExamples 3 and 4. The 9,10-dihydroxy-ocatanoic acid decyl ester wassynthesized by epoxidizing decyl oleate according to the epoxidationprocedure described in Example 5 followed by hydrolysis of the epoxideto form the corresponding diol using the synthetic procedure describedin Example 6. The triester, 9,10-bis-decanoyloxy-octadecanoic acid decylester, was synthesized by reacting 9,10-dihydroxy-ocatanoic acid decylester with decanoyl chloride (decanoic acid chloride) according to theprocedure described in Example 7. 9,10-Bis-decanoyloxy-octadecanoic aciddecyl ester has the following structure:

Example 9

The diesters and triester species described herein are themselvescapable of serving as lubricants. Referring to Table 1, the viscometric,low-temperature and oxidation stability properties are tabulated forthree different diester mixtures having been made in a manner such asdescribed in Example 2 (i.e., from an isomeric diol mixture), thetriesters of Examples 7 and 8, and several naphthenic oils commonlyemployed in industrial oils.

TABLE 1 KV₄₀, KV₁₀₀, Pour Cloud VI mm²/s mm²/s Pt., ° C. Pt., ° C. Ox.BN, h Diesters from C₁₄ diol isomers 109 16.3 3.6 −66 −69 19.5 andC₆-C₁₀ carboxylic acids Diesters from C₁₆ diol isomers 124 17.9 4 −51−51 25.8 and C₆-C₁₀ carboxylic acids Diesters from C₁₆ diol isomers 15224.4 5.2 −19 −18 38 and lauric acid Triester of Example 7 139 13.9 3.5−66 −48 Triester of Example 8 157 42.7 7.9 −29 −29 Mixture of Examples 7and 8 159 25.1 5.4 −39 −38 8.1 (50/50 wt. %) RAFFENE ® 750L <80 162.110.81 5 HYNAP ® N100HTS <80 20.50 3.58 −30

Example 10

Several saw guide oils were prepared and tested as set forth in Table 2.Saw Guide Oil 1 employed an ester base oil prepared as described inExample 2. Storage stability tests were used to observe the additivesolvencies over a 3 week period at −25° C. The additive solvencyobservations were made at the test temperature, and again, afterwarming, at room temperature. A liquid rating of 1 indicated that theoil was clear. A liquid rating of 5 indicated heavy cloud. A sedimentrating of 1 indicated that the oil had slight floc. The storagestability was deemed excellent if no sediment was noted at the bottom ofthe sample bottle.

TABLE 2 Saw Guide Oil 1 Saw Guide Oil 2 Component, wt. % Ester base oil96.68 — Naphthenic base oils — 96.68 Additive package comprising 3.323.32 corrosion inhibitor, emulsifier, tackifier, EP/anti- wear agent andfoam inhibitor Properties Kinematic Viscosity 27.71 43.48 at 40° C.,mm²/s Kinematic Viscosity 5.653 5.744 at 100° C., mm²/s Viscosity Index150 56 Test Initial Storage Stability 1/0 1/0 Rating, Liquid/SedimentStorage Stability Rating 5/Frozen 5/Frozen After 3 Weeks at −25° C.(read at −25° C.), Liquid/Sediment Storage Stability Rating Read 5/0 6/1After 3 Weeks at −25° C. (read at room temperature), Liquid/Sediment

From the foregoing results, it can be seen that the industrial oilcontaining an ester having a vicinal diester substituent exhibited muchimproved viscosity index and improved additive solubility. Even afterstoring of Saw Guide Oil 1 for three weeks at −25° C., no sediment orfloc was observed.

In summary, industrial oil formulations are provided which comprise anester having a vicinal diester substituent, and wherein at least aportion of the ester is bio-derived. Many such formulations of thepresent application are expected to favorably compete with similar,existing industrial oils comprising naphthenic base oils (e.g.,hydraulic oils, rock drill oils, saw guide oils, way oils). Suchformulations are generally expected to meet or exceed such existingformulations in a number of areas including, but not limited to,viscosity index, additive solvency, biodegradability, and/or toxicity.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing quantities, percentages orproportions, and other numerical values used in the specification andclaims, are to be understood as being modified in all instances by theterm “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that can vary depending upon thedesired properties sought to be obtained. It is noted that, as used inthis specification and the appended claims, the singular forms “a,”“an,” and “the,” include plural references unless expressly andunequivocally limited to one referent. As used herein, the term“include” and its grammatical variants are intended to be non-limiting,such that recitation of items in a list is not to the exclusion of otherlike items that can be substituted or added to the listed items. As usedherein, the term “comprising” means including elements or steps that areidentified following that term, but any such elements or steps are notexhaustive, and an embodiment can include other elements or steps.

Unless otherwise specified, the recitation of a genus of elements,materials or other components, from which an individual component ormixture of components can be selected, is intended to include allpossible sub-generic combinations of the listed components and mixturesthereof.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope is defined bythe claims, and can include other examples that occur to those skilledin the art. Such other examples are intended to be within the scope ofthe claims if they have structural elements that do not differ from theliteral language of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims. To an extent not inconsistent herewith, all citationsreferred to herein are hereby incorporated by reference.

1. An industrial oil comprising: a) a major amount of an ester base oilcomprised of at least one diester or triester species having a vicinaldiester substituent; and b) at least one additive, wherein theindustrial oil is selected from the group consisting of a hydraulic oil,a rock drill oil, a saw guide oil, and a way oil.
 2. The industrial oilof claim 1, having a viscosity index of at least
 140. 3. The industrialoil of claim 1, which is substantially free of any viscosity indeximprover.
 4. The industrial oil of claim 1, having a pour point of −10°C. or lower.
 5. The industrial oil of claim 1, wherein at least aportion of the ester base oil is bio-derived.
 6. The industrial oil ofclaim 1, wherein the diester species has a following structure:

wherein R¹, R², R³, and R⁴ are independently selected from hydrocarbongroups having from 2 to 17 carbon atoms.
 7. The industrial oil of claim1, wherein the diester species is derived from a process comprising: a)epoxidizing an olefin having from 8 to 16 carbon atoms to form anepoxide; b) hydrolyzing the epoxide to form a diol; and c) esterifyingthe diol with an esterifying agent having from 2 to 18 carbon atoms toform the diester species, wherein the esterifying agent is selected fromthe group consisting of carboxylic acids, acyl halides, acid anhydrides,and combinations thereof.
 8. The industrial oil of claim 1, wherein thediester species is derived from a process comprising: a) epoxidizing anolefin having from 8 to 16 carbon atoms to form an epoxide; and b)reacting the epoxide with an esterifying agent having from 2 to 18carbon atoms to form the diester species, wherein the esterifying agentis selected from the group consisting of carboxylic acids, acyl halides,acid anhydrides, and combinations thereof.
 9. The industrial oil ofclaim 1, wherein the triester species has a following structure:

wherein R⁵, R⁶, R⁷, and R⁸ are independently selected from hydrocarbongroups having from 2 to 20 carbon atoms and “n” is an integer from 2 to20.
 10. The industrial oil of claim 1, wherein the triester species isderived from a process comprising: a) esterifying a mono-unsaturatedfatty acid having from 10 to 22 carbon atoms with an alcohol to form anunsaturated ester; b) epoxidizing the unsaturated ester to form anepoxy-ester species comprising an epoxide ring; c) hydrolyzing theepoxide ring of the epoxy-ester species to form a dihydroxy-esterspecies; and d) esterifying the dihydroxy-ester species with anesterifying agent having from 2 to 18 carbon atoms to form the triesterspecies, wherein the esterifying agent is selected from the groupconsisting of carboxylic acids, acyl halides, acid anhydrides, andcombinations thereof.
 11. The industrial oil of claim 1, wherein theester base oil comprises a triester species having a followingstructure:

wherein R⁹, R¹⁰, R¹¹, and R¹² are independently selected fromhydrocarbon groups having from 2 to 20 carbon atoms, and wherein “n” isan integer from 2 to
 20. 12. The industrial oil of claim 1, wherein thetriester species is derived from a process comprising: a) reducing amono-unsaturated fatty acid to form an unsaturated alcohol; b)epoxidizing the unsaturated alcohol to form an epoxy-alcohol speciescomprising an epoxide ring; c) hydrolyzing the epoxide ring of theepoxy-alcohol species to form a triol; and d) esterifying the triol withan esterifying agent having from 2 to 18 carbon atoms to form thetriester species, wherein the esterifying agent is selected from thegroup consisting of carboxylic acids, acyl halides, acid anhydrides, andcombinations thereof.
 13. The industrial oil of claim 1, wherein thetriester species is derived from a process comprising: a) reducing amono-unsaturated fatty acid to form an unsaturated alcohol; b)epoxidizing the unsaturated alcohol to form an epoxy-alcohol speciescomprising an epoxide ring; and c) esterifying the epoxy-alcohol specieswith an esterifying agent having from 2 to 18 carbon atoms to form thetriester species, wherein the esterifying agent is selected from thegroup consisting of carboxylic acids, acyl halides, acid anhydrides, andcombinations thereof.
 14. The industrial oil of claim 1, wherein the atleast one additive is selected from the group consisting of pour pointdepressants, anti-wear agents, EP agents, detergents, dispersants,antioxidants, viscosity index improvers, friction modifiers,demulsifiers, foam inhibitors, corrosion inhibitors, rust inhibitors,seal swell agents, emulsifiers, wetting agents, lubricity improvers,metal deactivators, gelling agents, tackiness agents, bactericides,fungicides, thickeners, fluid-loss additives, and colorants.
 15. Amethod for improving an industrial oil, comprising: a) selecting anester base oil comprised of at least one diester or triester specieshaving a vicinal diester substituent; and b) replacing at least aportion of an original base oil in an original industrial oil with theester base oil to produce an improved industrial oil, wherein viscosityindex, additive solvency or both of the improved industrial oil ishigher compared to an original viscosity index, an original additivesolvency or both of the original industrial oil without the ester baseoil.
 16. The method of claim 15, wherein the original base oil is anaphthenic base oil.
 17. The method of claim 15, wherein the improvedindustrial oil is substantially free of any viscosity index improver.18. The method of claim 15, wherein the viscosity index of the improvedindustrial oil is at least 50 greater than the original viscosity indexof the original industrial oil.
 19. The method of claim 15, wherein theviscosity index of the improved industrial oil is at least 70 greaterthan the original viscosity index of the original industrial oil.